


colliding parallels

by pawn_vs_player



Series: Heavenly Bodies [1]
Category: Supernatural
Genre: Alternate Universe - Canon Divergence, Angel Family Feels, Big Brother Lucifer, Broken Families, Castiel Feels, Castiel Needs a Hug, Castiel is a Winchester, Cross-Posted on Tumblr, Defeating the Darkness, Emotional Constipation, Families of Choice, Gabriel Is Still Dead, Gen, I'm Sorry, Identity Issues, Lucifer Possessing Castiel, Lucifer could use a hug too, M/M, POV Lucifer, Post-Episode: s11e10 The Devil in the Details, Self-Sacrifice, even if he won't admit it
Language: English
Status: Completed
Published: 2016-02-13
Updated: 2016-02-13
Packaged: 2018-05-20 03:54:57
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,460
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5990848
Author URL: https://archiveofourown.org/users/pawn_vs_player/pseuds/pawn_vs_player
Summary: <blockquote class="userstuff">
              <p>Castiel is rather more influential on Lucifer than anyone had expected, but Lucifer won't let that get in the way of the plan.</p>
            </blockquote>





	colliding parallels

**Author's Note:**

> This isn't my first fanfiction, but it is my first one published on this account, and my first SPN fanfic published on AO3, so I'd really appreciate some feedback. Thanks!

_-Cas?_

_Guess again._

–

Sam’s staring again. Lucifer raises his eyes from the TV in front of them, blaring some reality trash that Cas apparently watches. “Yes, Sam?”

Sam blinks, shakes his shaggy head. “N-Nothing, Cas.” He drops his gaze back to the book on the table in front of him.

Lucifer breathes slowly, stares at the woman onscreen. _By Father, this is terrible. Why?_

 **_It is interesting_** _,_ Cas replies. **_Human entertainment is… strange, and varied, and intriguing. I wished to see, and understand._ **

_This is trash._

**_Perhaps so, to you_** _,_ Cas shrugs. **_But it has an audience. I wish to understand what is so entertaining for them to keep watching._ **

Looking at it like that… Lucifer takes his hand off the remote.

–

_You were a Seraph, right?_

_yes._

_How many of you were there?_

_before the Fall… hundreds. after… dozens._

_Now?_

_i believe i am the last. after Heaven closed, after we were banished… most did not survive. the few that did… Changed. they are angels no longer, and i do not wish to find them._

_How’d you survive, then?_

_i have no idea. i suppose my role in the Plan was not yet complete._

_Oh, yeah. Dad. He always had a soft spot for blue eyes._

_…this is a vessel, lucifer. i do not have blue eyes._

_That’s what you think._

–

Apparently, Cas and Winchester #1 are _not_ fucking. Cas had to yell this at Lucifer before he tried to kiss Dean.

 _Seriously, little bro?_ he asks, somewhere between stupefied and horrified. _I could sense your tension from the fucking Cage, before you entered it. It’s been what, seven years? Why the hell not?_

**_Dean does not wish to._ **

_Bullshit. I can_ feel _his longing, Cas, and I know you can too._

**_…you have already said it yourself, Lucifer. Others have agreed. I… It isn’t an option._ **

Lucifer blinks his borrowed eyes. _Really? What did I- …ohhhhhhh._ He pauses. _Seriously?_

Cas curls up defensively. **_It’s a fairly simple concept, Lucifer, one that you have already grasped. I do not understand your surprise._ **

_I…_

It _is_ simple, and he has already said it, imprinted it. But… it’s so _visceral,_ feeling the waves of Cas’ self-loathing and guilt and resignation flowing over his consciousness like a spilled glass of arsenic. It’s vile, and thick, and toxic. It makes Lucifer’s stomach tip, makes him want to open his vessel’s mouth and eject the breakfast he had with the brothers.

 _…I did not comprehend it, before,_ he says delicately, and feels the sting of Cas’ surprise.

 **_Oh,_ ** Cas says, and that’s that.

–

_what was so terrible about the Cage? i mean… why was it such a punishment?_

_I was trapped, alone, in a freezer box in the core of Hell for millennia. Isn’t that enough?_

_…it doesn’t seem like much of a punishment to me, that’s all. it… doesn’t seem so drastic a change._

_You’re not me, Cas._

–

For the best hunters in the business, they really are unobservant. Or rather, because Lucifer is honest to himself _(and Cas)_ at least, they are too wrapped up in other things and each other to really notice that ‘Cas’ isn’t acting like himself, and when they do pick up on the little cues that Lucifer drops, they brush it off.

Well, the Winchesters always have been good at denial and repression.

–

_((And Cas is a Winchester too, now, a Winchester with the power and trueform of an angel, a being unlike anything else left in this world, and Lucifer might be scared if he wasn’t so fascinated by what his little brother is becoming.))_

–

 _How long have you been Cas?_ Lucifer asks one day, a little more than two weeks into the deception. He’s been mostly holed up in the bunker while the boys hunt and look for Amara and Crowley- except when Crowley gets back to him or when there’s other business for him to attend to. He’s honestly curious as to how long he can make this last.

He feels Cas’ confusion, a frown spreading across a tilting face. **_What do you mean?_ **

_When did you go from ‘Castiel, Angel of the Lord’,_ and yes Lucifer saw that memory, his little brother’s head is far more interesting than the garbage on TV, _to ‘Cas, honorary member of the Winchester clan and on-call angel?’_

There is a long pause while Cas thinks.

 **_…I do not know_** _,_ he says eventually. Lucifer’s Grace curls over Cas, smoothing and prodding in turns, delving into the little folds and pinching out the errant sparks. Cas shudders under the touch, wings uncurling inside the cramped vessel, and Lucifer’s wings come around, pinning Cas’ to his sides.

 _Do you need to?_ Lucifer asks, forgetting that he was the one to ask when in the first place. He cocks his head, looks at Cas. _Why is it important? Why does it matter, when you went from Castiel to Cas?_

_((Why does it bother me?))_

**_I do not know,_ ** Cas says cautiously, looking back at Lucifer, wings pressed to his sides and back submissively. Lucifer’s own wings and Grace pull away, back to their previously-allotted spaces. Cas’ curiosity rolls across Lucifer. **_It doesn’t particularly matter to me. This is who I am, now, and I know that. And I know that 'Castiel’ is not someone I can return to being. That is that, and it doesn’t bother me now, if it ever did._ **

There is a pause.

 **_…does it bother you?_ ** Cas asks, and Lucifer doesn’t answer.

–

_Cas?_

_yes?_

_How powerful are you?_

_…can you not feel it?_

_Cas, we’re squished inside your vessel together, I’m suffocating you, and I’ve underestimated you far too many times. If I was to leave, right this moment, what would you be capable of?_

_…_

_…I see._

_why do you ask?_

_…Backup plan._

_what?_

_Amara’s the biggest fucking fish in this ocean, Cas. I_ might _be able to take her on my own, but…_

_…you need assistance._

_Well, I’d rather not die or be consumed by my creepy-ass aunt, so yes._

_why did you tell me you could, then?_

_I can. But in this case, you’re more preferable than Sammy. He may be my true vessel, but he’s only human. You, on the other hand, have a Grace._

_you plan to drain me._

_If it comes to that, yes._

_…i see. and… what would happen if she were to consume us?_

_…I’d see my baby brothers again. And maybe we’d get to die, and maybe stay that way. I don’t know. Dad never explained what happened, exactly, just said it was the opposite of Him. Of Creation, of Life, of Love. All that sappy Hallmark shit._

_…_

_Cas?_

_i have an idea._

–

Crowley stares at him.

“You’re different,” he mutters.

Lucifer cocks his head, raises an eyebrow, grins slightly. “Really? How?”

Crowley shrugs. “I dunno, you’re…” He hesitates. “You’re… different from how I remember.”

Lucifer laughs. “Aww, Crowley, just because you’re used to seeing this-” He goes stiff and still, lets his arms drop and his mouth flatten, before springing back into natural motion- “with this body, doesn’t mean I’m not still me!”

Crowley shrugs. “Whatever you say.”

Lucifer smiles. “Indeed.”

–

_does he have a point?_

_I don’t know, you tell me._

_how can i? i haven’t seen anything except your trueform since i agreed. i don’t know if you’re acting different to them or not._

_…_

_lucifer, i don’t know._

_Alright, alright. I believe you._

–

“Cas?” Dean asks, staring at the hand on his shoulder, and Lucifer feels Cas shake inside him.

 _What?_ he asks, actual fear curling in his throat. _What did I do?_

 **_WRONG SHOULDER,_ ** Cas hisses, but it rings in Lucifer’s ears like the knolling of a church bell.

He brings his _(stolen)_ eyes up from his _(stolen)_ hand on Dean’s shoulder, looks at Dean’s eyes and waits for the hunter to look back.

 _What do you want me to do,_ he asks.

Cas shivers.

 **_What you must,_ ** he says, and Lucifer shields against the tidal waves of emotion rolling off his little brother.

He has a role to play.

“Aw, Dean,” he says, and stops pulling up Cas’ movements, his speech patterns, the way he sits. “Four weeks? Really?”

Dean steps back, hand dropping to his empty back pocket, and Lucifer sees the flash of fear in his eyes.

“Nearly a month,” Lucifer continues, following Dean until Dean’s back is pressed to the wall and Lucifer’s a few inches away from him. “Really? I thought you knew your angel better than that, Dean. _He_ thought so, too, y'know.”

Lucifer can feel Cas’ trembling, the way his Grace is curled right around itself, the way Dean’s obliviousness is just another nail shot through the ground to thud into Cas’ already-buried coffin. And it makes something inside Lucifer burn and crackle, like paper thrown into a fireplace. He forces his hands to remain loose, shoves them into his pockets when that fails. Hopefully Dean will be focused on other things.

“But I guess we were both wrong,” he says lightly. Dean flinches, and- that wasn’t expected, by either Cas or Lucifer.

“I-”

“Ah ah ah,” Lucifer says, grinning with all the teeth he can. “Not your turn, Dean.” He pins Dean to the wall with a flick of his fingers, his chest twinging in satisfaction at the resulting grunt, and perches on the table behind him. He leans back on his hands and grins roughly at Dean.

“Where should I start… hmm…” He snaps his fingers. “Whaddaya wanna hear about, Deanie?” He pauses. “Your turn now.”

Dean snarls. “Get out of Cas!”

Lucifer tuts. Cas roils inside him. “Afraid that’s not an option at the moment, Dean. I’ll be here for a while.”

Dean glares. Lucifer laughs.

“I’m not Cas, Deanie-weenie. I will not bow to the threat of your hatred; I could give less of a shit if you hate me more for this.”

His chest twinges. Cas flattens out, the edges of his Grace curling into the frayed hems of Lucifer’s.

His smile remains static. “Cas and I have a deal, see,” he says calmly, watching the emotions chase each other across Dean’s face. “He lets me out, hosts me… and I clean up your mess for you.”

Dean goes still. “Amara.”

“Ding ding ding!” Lucifer leaps off the table, starts swaying around the room. “Give the man a prize!” He pauses. “Actually, nah, I think me doing this is prize enough.”

“Get. Out. Of. Cas.”

Lucifer sighs, strides forward, slides a finger under Dean’s chin. “No can do, Dean. How many times do I need to say it before you understand?”

Footsteps in the doorway, a choked little noise. Lucifer waves his hand and Sam slams into the wall.

“Sam!” Dean yells, predictable as ever. Cas curls tight against Lucifer, and the ember burning in Lucifer’s chest sparks hotter.

“He’ll be fine,” Lucifer hisses, “nothing you two haven’t gotten through before.” He flicks his hand, and Sam freezes against the wall, half-sitting up with one hand over his head. He turns away from Dean and smiles at his true vessel.

“Anything to say, Sammy?”

“How?“

Lucifer tuts. “You know the answer, Sammy. Cas said yes.”

“Amara,” Dean puts in, and Sam swallows.

“What are you going to do?”

Lucifer grins. “Not much of a surprise attack if I tell, is it?”

Dean starts fighting his Grace again. “Let us go, you son of a bitch! Give m- give us Cas!”

Lucifer chuckles. “Dean. Get it into your head already.” He leans in, smile melting off his face as Grace surges behind his borrowed blue eyes. “Cas. Said. Yes. I’m here until our deal is fulfilled, and depending on where we are when that’s done, I’ll leave it to Cas.” He can feel Dean’s quick pants against his face, hear his heartbeat thundering in his neck. Lucifer doesn’t smile because he doesn’t need to, and the act is wearing so thin.

“I’m here to do my job,” he says, so quiet, and Dean goes utterly still under his own power. Lucifer’s gaze burns against Dean’s. “I will take care of Amara, and you and your brother will survive. And if Cas and I survive, I’ll leave, and I’ll find someone else.”

Dean inhales. Swallows.

[Cas?] he prays.

Cas shakes inside Lucifer, Grace extending unconscious, shuddering tendrils toward Dean. Lucifer’s eyes flare as he shuts them down, curls his own Grace around Cas, to keep that from happening again but also to sooth his brother’s desperate shivers.

 **_Dean,_ ** Cas says, despair and hope and resignation twined together in a diamond-sharp stab through Lucifer’s consciousness. **_Dean._ **

_Cas,_ Lucifer warns, and Cas draws himself in.

Lucifer looks into Dean, sees the thin cord of Grace twined through Dean’s gold and emerald soul, and sighs.

“Little brother really has an attachment, huh,” he breathes, almost unaware that it’s aloud. Dean blinks.

“What?”

Lucifer smirks, leans back. “See ya, boys,” he says, raising his hand. “I have a deal to fulfill.”

“No!” Dean shouts. Sam’s eyes are pits in his pale face, and Lucifer remembers Sam in the Cage, both times, remembers Sam hosting him and Sam saying no. Reaches out, without meaning to, and sees Sam through Cas’ eyes.

Makes eye contact with Sam, now, fingers coming together.

He winks.

He is abruptly elsewhere, and he sighs.

 _How do you do it?_ he asks, not expecting an answer.

 ** _I stopped fighting,_** is Cas’ reply, and Lucifer goes still and quiet.

–

_/You know… if you were a little less moral, I could go for you._

_what?_

_/You’re so like your brother in some ways… truly, if you didn’t love the humans so much, if you were a little more prone to chaos and darkness for their own sake- you’d be so much like him._

_i-i am not like Lucifer._

_/Keep telling yourself that, darling._

–

 **_Rowena was right,_ ** Cas says, a month and a half in, and Lucifer digs for the memory.

 _How so?_ he asks, genuinely curious.

 ** _I’ve thought about it, and… she’s right, really._** Cas pauses, collects his thoughts. **_You Fell for Father, and I Fell for them. For Dean, and Sam, but for the rest of them too._**

 _I loved Father,_ Lucifer says, remembering the last time he said that. Cas nods.

**_And I love Dean and Sam. And the rest of them. But I was reinstated, and you… well. You were sent back to the Cage._ **

Cas hesitates.

 **_I love humanity,_ ** he says. **_You despise it. Amara wishes to destroy it, and Father created it._ **

_A Creator and a Destroyer,_ Lucifer murmurs. _A lover and a loather._

He chuckles bitterly. _He always did love parallels._

 **_What are we to do?_ ** Cas whispers. **_Going by that logic, you are more allied with Amara than me._ **

Lucifer smiles.

 _In theory,_ he concedes. _But in practice…_

–

_where will you go, after?_

_I don’t know._

 

_why are you honest with me?_

_Who else would I be honest with?_

 

_are we going to die?_

_Maybe._

 

_why me?_

_You know why._

 

_do you hate me?_

_…I used to._

 

_am i broken?_

_You aren’t unfixable._

–

“Dean,” Lucifer breathes, looking at the hunter through the ring of holy fire. “You fucking moron.”

Dean glares at him. “Get out of Cas.”

“This isn’t a good plan,” Lucifer says, eyes flicking across the flames. “This is, in fact, a shitty, shitty plan.”

“Give me Cas,” Dean says, and Lucifer snarls.

“You want him so bad?” he asks, and Cas panics. **_No, Lucifer, no! You have to stay!_ **

_You need to talk to him for him to understand,_ Lucifer says, and meets Dean’s eyes.

“I’m not going anywhere,” he warns, and slides into the vessel, shoving Cas forward.

He drifts. Watches Cas’ Grace fluctuate as the conversation goes on, ignores the actual words. He doesn’t need to know.

Cas pokes him. **_Come back. He will release us._ **

Lucifer grins as the mouth becomes his again. He looks at Dean, cocks an eyebrow. “Come around, have you?”

Dean growls under his breath, but he grabs a hose.

–

| _why did you do it?_

_because i had to._

_|there are other players in this game, castiel. other candidates._

_not in this round, Crowley. you know that._

_|…yeah, i know._

_Lucifer wishes to discuss the third seal._

_|of course. send him back._

–

Lucifer holds the seven seals in his arms and stares at Dean and Sam and Crowley. He doesn’t smile, just makes eye contact as he drops one item into each of their arms: Dean gets Raziel’s feather, Sam Saraqael’s dagger, and Crowley Raguel’s curled whip. Lucifer holds onto the remnants of Raphael’s staff, Gabriel’s horn, and the hilt of Michael’s sword. His own seal is curled inside his Grace, ready to be released.

“You’ll be standing in for my brothers,” he says, and doesn’t make eye contact anymore. “Crowley, here- Dean, here- Sam, here.”

He takes a breath, and blinks twice.

“ **|AMARA,|** ” he says in his True Voice, and suppresses his grin at Sam and Dean’s wince. “ **|COME.|** ”

And there Amara is.

“Lucifer,” she breathes, a smile lighting upon her lips. “It’s been so long. I’ve missed you, my favorite nephew.”

Lucifer snarls at her. “I bet you have.”

//dark tendrils curling over him, around him, _into_ him, pinning him and covering his mouth and blocking his Grace so he can’t scream, probing and exploring places he _did not_ want probed//

Amara pauses. “Really, are you still sore over that?”

“ _Every night,_ ” Lucifer hisses. “Until we locked you away. I’m not the forgiving or forgetting type, remember?”

Cas pets at him, trying for comfort. Lucifer reigns himself in.

“But we aren’t here about that,” he says, voice too even.

Amara cocks an eyebrow. “Why, then?” Her eyes skip to Dean. “To hand me my prize?”

Dean glares. Lucifer chuckles.

“Nope.”

Before Amara can blink, he’s in front of her and Raphael’s staff is in her chest. She drags in a gasp, stumbling back, and Sam darts forward to slice Saraqael’s dagger across her pale throat. Crowley’s hand snaps out, the blessed whip slashing over her wrists, curling around them and making her stumble, and Dean catches Lucifer’s eyes as he tosses the feather.

It explodes at Amara’s feet, Grace knocking her to the ground. She drags at Raphael’s staff, lodged between her lungs; stares up at Lucifer as he brings Gabriel’s horn to his lips.

He blows, sound crashing into and through her, and presses Michael’s hilt to her open mouth.

“ _Fuck you,_ ” he breathes, and his hand presses against where her heart would be.

The ball of light inside him, the pure heavenly power he’s been carrying since she was sealed the first time, bursts through his fingers. Cas screams as it tears through him, Lucifer’s eyes glowing with his Grace, and Amara stares back at blackness wraps around them both.

\\\| **YOU’RE COMING WITH ME,** |// she bellows, and Lucifer grins. Cas smiles tiredly behind him.

 _|W_ **_o_ ** _u_ **_l_ ** _d_ **_n_ ** _’_ **_t_ ** _w_ **_a_ ** _n_ **_t_ ** _i_ **_t_ ** _a_ **_n_ ** _y_ **_o_ ** _t_ **_h_ ** _e_ **_r_ ** _w_ **_a_ ** _y_ ,| they agree, and Cas shoves his Grace out alongside Lucifer’s, and Love twines into Hatred, and they gasp and shudder as they _combine,_ and Amara screams, and the Darkness envelops them and Cas’ connection to Dean _snaps_ and Lucifer can’t feel Sam anymore

–

_They’ll mourn you, you know._

_they can deal with grief. they’ll forget me soon enough._

_I don’t think so._

_we’ll find out, won’t we?_

–

 ~~**\|Lucifer,|/**~~ his Father breathes, and tears drip down Lucifer’s cheeks.

_Dad?_

~~**\|I have missed you,|/**~~ He murmurs, and hugs Lucifer.

Lucifer cries hot tears against his Father’s being, and He strokes Lucifer’s hair.

–

“Cas,” God says, and Cas stares.

“Chuck Shurley.”

“Hey.” He smiles, and Cas smiles back.

“I wondered,” he says, and He puts a hand on Cas’ shoulder.

“Do you want to go back?”

Cas hesitates.

“Dean,” he says finally, and God kisses his forehead.

“I can send you to him.”

“And… Lucifer?” Cas asks.

“He has done more than I’d hoped, thanks to you,” God replies. “He will remain with me, for the rest of his recovery. He has… much to learn, much to remember.”

God touches Cas’ forehead.

“As do you,” He whispers, and Cas is loved, and Cas loves, and Cas is worth all the love his Father has for him.

Cas stumbles. He catches Cas, and His eyes are serious as they bore into Cas’.

“Do not let anyone make you believe that again,” God says. Cas nods shakily.

“Y-Yes, Father.”

God kisses Cas’ forehead. “Go,” he breathes, and Cas is gone.

–

~~**Are you ready, my son?** ~~

_Yes._

–

Cas opens his eyes.

He is where it began.

His cellphone is in his coat pocket.

He opens it, presses #1 on speed dial.

“Dean?”

“Cas?”

Cas smiles.

**Author's Note:**

> I'm currently working on an extended version of this story, with a lot more backstory, angel family feels, and character. I have no idea when that'll be done, though...


End file.
